The Care Inspectorate received 4,696 complaints about care services in 2017/18 a 10 per cent increase compared to the previous year and up from 4,440 in 2014/15.
The watchdog say they received at least one complaint for about 76 per cent of private sector care homes for older people in 2017/18 a higher rate than the proportions in other sectors of provision like local authority or health boards.
However, the organisation said that although levels of complaints received have risen over this period, it does not necessarily indicate that quality of care is in decline.
Comparing 2014/15 to 2017/18, the percentage of services graded good, very good or excellent in all “quality themes” has remained consistently high at 87 per cent and 89 per cent.
Almost half of the complaints (47 per cent) investigated over the four years were about care homes while 21 per cent of the complaints investigated were about daycare of children services.
Peter Macleod, chief executive of the Care Inspectorate, said: “We know from our inspections the majority of care services in Scotland perform well, and people generally experience good-quality, compassionate care which meets their needs, protects their rights and promotes their choices.
“However, where things are not good enough it is important that services improve, quickly.
“Our complaints procedure allows people who experience care, their friends and families, and others, to raise with us concerns they have about care services in Scotland.”
Care services operating in Scotland must be registered with the watchdog and there are around 13,300 on their records.
Scottish Conservatives health spokesperson, Miles Briggs, said: “This report shows the majority of care services in Scotland are performing well, however, the number of complaints received by the care inspectorate is on the rise.”
A Scottish Government spokesperson said: “We welcome this report and recognise the important role the Care Inspectorate plays in driving improvement in care services.”